Helmet communication system



June 21, 1960 A c. E. CUNNINGHAM 2,942,072

HELMET comwUNIcATroN SYSTEM Filed June 17, 1957 AT TORN'E Y e claims. (cries-15o This invention relatesv to helmet communications sys: tems and more particularly to 'such systems in vwhich ponents therein perform their intended functions without interference with the usefulness and utility of the helmet.

Heretofore helmet communications have been accom plished by means of a pair of earphones imbedded in the helmet liner for listening and some type of microphone positioned either on the throat or near lthe mouth area for picking up speech. The throat microphone, consisting of a pair of carbon filled elements placed on either -side of the larynx, came into use as a result of oxygen mask developments interfering with communications and vice, versa. The throat microphone had several disad vantages, the dynamic-range wasv poor due to inherent self noise, there was no discrimination against outside noise, the intelligibility was considered medium, individual Patented June 21, 1960 72 Another 'object `is the provision of a helmet communi# 'cations system wherein the speakers voice is picked up through a bone conduction medium. r Another object is the provision of a helmet having a microphone mounted therein for contacting the wea-rers forehead. t i Another 'object is the provision of a helmet having a forehead contacting microphone embedded the inner lining thereof. l i

Another object. is the provision ofa helmet wherein communication system components therein will not in'- teifere with face mask placement or oxygen equipment.

Another object is the provision of a helmet wherein communication system; components therein do notneed physical adjustment for use or for removing or` putting on the helmet. y

Another object is the provision of a helmet 'wherein the microphone and earphone components ofthe communications system therein are placed so as to be exposed to a minimum of outside noise.

Other objects and features of the present invention will be readily apparent to those skilled in the art from the following specification and appended drawings wherein is illustrated a preferred form of the invention, and in which: f

Figure 1 is a perspective view ofthe helmet with parts broken away to better show itsI construction,

differences in human throats gave varied results and the microphone was hard to maintain in position,

Later a differential dynamic microphone was integrated into the oxygen mask and with the development of face= plated helmets, ducted microphones were placed inside the front of the helmet with the duct opening at the speakers lips. These microphones also had certain disadvantages, breathing noises picked up interfered with intelligibility, its close proximity to the mouth made it a very personal item, its positionhad to be continually adjusted, it was bulky and it did not provide enough disx crimination to loud noise.

The helmet communications system comprising the prsent invention consists of a pair of standard earphones ernbedded in the helmet linerfor listening andia Contact microphone placed 4in the helmet liner so as to make contact with the forehead area of the operator. The speakers voice is picked up by the microphone through the medium of bone conduction. Either a single element may be used at one location on the forehead or several elements may be used placed at several positions over the forehead. An associated miniaturized preamplifier, with proper bandf pass characteristics to insure intelligibility, may be placed in any suitable place in the same helmet liner. Microphone housings may be designed to include the preamplier if desired. The advantages of this system include the following:

(l) There are very little individual differences in human forehead flesh thickness and microphone operation would thus be uniform for all users.

(2) No adjustments are necessary and good contact is always assured.

(3) The microphone would not be considered a personal item and use by others would not be objectionable.

(4) There is no noise pickup from breathing and the helmet liner provides good protection from outside noise.

(5) The hehnet may now be more compactly designed without interference with its communication system.

(6) The microphone presents no hazard in escapement from high performance aircraft.

It is therefore an object of this invention to provide means for sensing vocal intelligence through a bone conduction medium.

Figure 2 is a plan view of the forehead microphone, 'and Y, Figure 3 is a cross sectional view taken along the 4line 3'-3 of Figure 1. Y v

v Referring now to Figure 1 there is shown a pilot helmet 11` comprising an outer shell 12, an inner detachable 1in ing 13, a face mask 14, and a neck rim lSadapted to en-` gage collar 16 for air tight connection with a pressurized suit l17. The face mask 14 pivots about a separable hinge 18 at the top and is fastened by a quick-release latch 19 at the bottom. Breathing apparatus may be connected to the mask by a snitable connection 21. The mask conipletely coves the face opening of th helmet and when attached makes the helmet airtight, Y p

Inside the helmet is a removable lining ll3. While any manner of securing the lining to the helmet may be made, in the preferred embodiment snap fastenes are used about the face opening and' around the e'ap ones. Artipper is us'ed around the neck opening. lining is p'rferably of a protective resilient material having sound absorbing qualities. Between the inner head-contacting surface of lining 13 and the outer shell 12 is mounted a set of earphones 22, a miniaturized preamplifier circuit and components 23 and suitable leads 24 thereto and to a forehead contacting bone conduction microphone 26. These elements may be secured to the shell 12 or the lining 13 as desired. The lining may lie over the elements or recesses formed in the lining to receive them and thus present a uniform smooth surface for contact with the wearers head.

Bordening the face cut-out portion of the helmet is a pliable strip 27 of resilient material, such as sponge rubber for example. This strip forms a face contacting surface which divides the helmet into two compartments, the face masked area where oxygen is supplied and the rear portion where the communications equipment is placed. This strip, when contacting the face, tends to retard escapement of oxygen from the forward area and also serves to seal out external noise and contain within the helmet intelligence received via the earphones.

Embedded within a recessed portion in the s-trip adjacent the wearers forehead is a bone conduction microphone 26. This microphone is preferably attached to the shell by a light leaf spring 25 so that the microphone is gently urged into contact with the wearers forehead even when the wearer turns his head or pivots his head bacltwardly..V Since there" are no known micro.

phones commercially available which were designed for this purpose, a small crystal mike 28 with a pair of actuating `'forehead contactingA members 29 was used.1 jThis is shownjinFigure 2." The forehead contacting area was then enlarged by attaching a at thin plate V31 to the members. .This plate ,relieved discomforting localized pressure on the wearers forehead which was present before the plate was used. This plate also provides better contact and fis more responsive to the vibrations of the foreheadwhen the wearer speaks; 1

As shown in Figure 3 earphone 22 is positionedV by a pocket in lining 13. The earphone may beV inserted into the pocketthrough a slit 32 at the top. The printed circuit board with components thereon comprising the preamplifier .23 Vmay be similarly mounted. While the earphones are' obviously. placed in close proximity to the wearers'ears, the'preamplifier may be conveniently positioned as desired. lThe neck portion of thehelmet terminates in a rim 15 'adapted to engage collar 16 of suit 17. An O-ring 33 maintains the airtight relationship and a suitable latch (not shown) is provided forreleasably fastening the helmet torthe suit. Inside the rim 15 is Vmounted a terminal connection block 34 for connecting leads 24 from the helmet communications componentsto external circuitry. A protective guard 36 prevents damage to the connectors 37 on the block in mounting and removing the helmet. In the preferred embodiment connectors 37 are electrically conductive coatings on a printed circuit board althoughother typesmay be used. A mounting block `38 is mountedon the inside wall of collar 16 to support a mating terminal connection 39 wherein mating terminals to external circuit leadsl are housed. In this manner electrical connection to the helmet communications equipment is automatically made when the helmet is placed over the wearers head and onto the suit. Electrical connection is automatically broken when the lhelmet is removed. Y

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto as Vmany variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation Within the terms of the following claims.

What I c1aim'is: Y l. A helmet communications system comprising in combination a helmet, earphones in said helmet mounted for placement in close proximity to the ears of the helmet wearer, and a voice sensing device mounted in said helmet for contact with the forehead of said wearer thereof.

2. A helmet having an inner lining, a recessed area in said lining adjacent the forehead of the wearer thereof, and a bone conductionsensing device positioned in said recess for contacting said wearers forehead.

3. A helmet, an' inner lining in said helmet, said inner lining having a microphone therein mounted vfor contact Withxthe forehead of a wearer of said helmet, a miniaturized preamplier circuit in said helmetV electrically connected to said microphone, earphones in said helmet tted therein in close proximity to said wearers ears, and readily detachable lleads for interconnecting said earphones and preamplilier to 'external circuitry.

4. A helmet communications system comprising a helmet having an inner lining adapted to fit about the face ofl its v-wearer,l a microphone in said lining having a plate i thereonfor contacting said wearers forehead, said plate receiving lbone conduction vibrations from said forehead when said wearer vspeaks and actuates said microphone in` response thereto, and means in said helmet for communicating audio intelligence to said wearer.

5. A helmet comprising a protective outer shell and a soft pliableinner lining, an airtight removable mask fitted over the face portion thereof, said inner lining 'fitting in contact with the wearers forehead, temples, jaws and chin, earphones mounted in said helmet in close proximity with said wearers ears, vibration sensing means mounted'tin said. helmet for contacting said Ywearers forehead, means permitting oxygenV ow to said wearers face, and means for releasably securing said helmet to a garment WornA by. said wearer.

6. A bone conduction microphone for sensing vocal utterances, said microphone comprising vibration actuating means, `a relatively thin at plate for contacting a persons forehead, said plate being connected to said actuating means, a helmet for placement over said persons head, and means for yieldingly supporting said microphone within said helmet for gently urging said plate into contacting engagement with said persons forehead.

References Cited in the le ofthis patent UNITED STATES PATENTS 1,085,621 Lutenberger Feb. 3,1914 2,451,317 Blair et a1. ocr. 12, 194s 2,535,063 Halstead Dec. 26, i) 

